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Despite being present in trace amounts, ethyl esters play a crucial role as flavour compounds in lager beer. In yeast, ethyl hexanoate, ethyl octanoate and ethyl decanoate, responsible for fruity and floral taste tones, are synthesized from the toxic medium chain acyl-CoA intermediates released by the fatty acid synthase complex during the fatty acid biosynthesis, as a protective mechanism. The aim of this study was to enhance the production of ethyl esters in the hybrid lager brewing yeast Saccharomyces pastorianus by improving the medium chain acyl-CoA precursor supply. Through CRISPR-Cas9-based genetic engineering, specific FAS1 and FAS2 genes harbouring mutations in domains of the fatty acid synthesis complex were overexpressed in a single and combinatorial approach. These mutations in the ScFAS genes led to specific overproduction of the respective ethyl esters: overexpression of ScFAS1 I306A and ScFAS2 G1250S significantly improved ethyl hexanoate production and ScFAS1 R1834K boosted the ethyl octanoate production. Combinations of ScFAS1 mutant genes with ScFAS2 G1250S greatly enhanced predictably the final ethyl ester concentrations in cultures grown on full malt wort, but also resulted in increased levels of free medium chain fatty acids causing alterations in flavour profiles. Finally, the elevated medium chain fatty acid pool was directed towards the ethyl esters by overexpressing the esterase ScEEB1. The genetically modified S. pastorianus strains were utilized in lager beer production, and the resulting beverage exhibited significantly altered flavour profiles, thereby greatly expanding the possibilities of the flavour palette of lager beers. • Ethyl esters play a crucial role as flavour compounds in lager beer. • Enhancing medium chain acyl-CoA improves production of ethyl esters in lager yeast. • Alleles ScFAS1 I306A and ScFAS2 G1250S improves ethyl hexanoate production in lager yeast. • Allele ScFAS1 R1834K boosted ethyl octanoate production in S. pastorianus. • Engineering of ethyl ester synthesis aids customizing aroma profiles lager yeast. [ABSTRACT FROM AUTHOR]

As an essential strategy for transitioning towards a circular economy for a sustainable society, food waste (FW) can be efficiently used for the biological production of added-value compounds such as medium chain fatty acids (MCFAs). The microbial conversion of FW into MCFAs is an ecofriendly, sustainable and cost-effective approach that reduces the great pressure on land and water resources associated with traditional MCFAs production methods. Among the MCFAs, caproate holds high economic value and a large market size due to its widespread application in several industrial areas. The biological production of caproate from FW is a complex mechanism that requires a deep understanding of microbial dynamics, metabolic potentialities and functional stability for process optimization and large-scale application. This review aims to outline the existing knowledge about bacterial component involved in the caproate production from FW. Innovative approaches to address current research gaps, ensuring a thorough and up-to-date understanding of the biological caproate production are herein identified and proposed. [ABSTRACT FROM AUTHOR]

Static infusion of oak chips in wine is a common practice during wine ageing, aimed at improving sensory properties and stability of wines. The wine/chips contact required to reach the desired effect can last several weeks or months. A low-pressure continuous dynamic (LPCD) extractor in which a closed-circle, low-pressure continuous flow of wine passes through an extraction cell filled with chips, was evaluated as a tool to tune red wine properties in few hours. The aim of this work was to evaluate the effect of the use of a LPCD extractor the effect on color, volatile compounds and sensory properties of a Primitivo wine, as well as to assess the combined effect of LPCD extractor, passive microxygenation through polyethylenetereftalate (PET) containers and exogenous tannins.Their combined effect caused a significant increase of stabilized pigments was observed, without compromising the aroma profile.LPCD extraction, passive micro-oxygenation through plastic materials and enological tannins can be considered as a low-cost, and potentially low-impact, integrated technological platform suitable to tune wine sensory properties and stability, when either traditional approaches (such as barrel aging) or other assisted extraction technologies are not applicable or preferred, even in small wineries.

n-Caproate, which is produced via chain elongation (CE) using waste biomass, can supply various fossil-derived products, thus advancing the realization of carbon neutrality. Ammonia released from the degradation of nitrogen-rich waste biomass can act as a nutrient or an inhibitor in anaerobic bioprocesses, including CE, with the distinction being primarily dependent on its concentration. Currently, the optimal concentration of ammonia and the threshold of toxicity for open-culture n-caproate production using ethanol as an electron donor, along with the underlying mechanisms, remain unclear. This study revealed that the optimal concentration of ammonia for n-caproate production was 2.0 g∙L−1, whereas concentrations exceeding this threshold markedly suppressed the CE performance. Exploration of the mechanism revealed the involvement of two forms of ammonia (i.e., ammonium ions and free ammonia) in this inhibitory behavior. High ammonia levels (5.0 g∙L−1) induced excessive ethanol oxidation and suppressed the reverse β-oxidation (RBO) process, directly leading to the enhanced activities of enzymes (phosphotransacetylase and acetate kinase) responsible for acetate formation and diminished activities of butyryl-coenzyme A (CoA):acetyl-CoA transferase, caproyl-CoA:butyryl-CoA transferase, and caproyl-CoA:acetyl-CoA transferase that are involved in the syntheses of n-butyrate and n-caproate. Furthermore, the composition of the microbial community shifted from Paraclostridium dominance (at 0.1 g∙L−1 ammonia) to a co-dominance of Fermentimonas, Clostridium sensu stricto 12, and Clostridium sensu stricto 15 at 2.0 g∙L−1 ammonia. However, these CE-functional bacteria were mostly absent in the presence of excessive ammonia (5.0 g∙L−1 ammonia). Metagenomic analysis revealed the upregulation of functions such as RBO, fatty acid synthesis, K+ efflux, adenosine triphosphatase (ATPase) metabolism, and metal cation export in the presence of 2.0 g∙L−1 ammonia, collectively contributing to enhanced n-caproate production. Conversely, the aforementioned functions (excluding metal cation export) and K+ influx were suppressed by excessive ammonia, undermining both ammonia detoxification and n-caproate biosynthesis. The comprehensive elucidation of ammonia-driven mechanisms influencing n-caproate production, as provided in this study, is expected to inspire researchers to devise effective strategies to alleviate ammonia-induced inhibition.

The pretreatment of activated sludge can improve the resource recovery capacity, and the combination of surfactants and carbon chain extension（CE） technology can increase the yield of high-value MCFA. APG06 and CTAB combined with ethanol as electron donors were used to study the efficiency of medium chain fatty acid production from activated sludge under anaerobic fermentation, and the MCFA production before and after ethanol addition was investigated. It was found that the output of VFA was the highest when ethanol was not added, while the output of MCFA increased significantly after ethanol was added. The addition of ethanol is beneficial to CE reaction and promotes the conversion of VFA to MCFA. The microbial community indicated that high doses of APG06 and CTAB were more favorable to the CE reaction process. [ABSTRACT FROM AUTHOR]

Free fatty acids (FFA) have gained research interest owing to their functions in both local and systemic immune regulation. Changes in the serum levels of anti‐inflammatory short chain fatty acids (SCFA), primarily derived from the gut microbiota, and pro‐inflammatory medium (MCFA) and long (LCFA) chain fatty acids, derived from either the gut microbiota or the diet, have been associated with autoimmunity. Circulating FFA were retrospectively analysed by a gas chromatography–mass spectrometry method in the serum of 18 patients with pemphigus vulgaris (PV) at the baseline and 6 months (n = 10) after immunosuppressive treatments, and 18 healthy controls (HC). Circulating FFA were correlated with the Pemphigus Disease Area Index (PDAI) and serum concentrations of interferon‐gamma (IFN‐γ), Interleukin (IL)‐17A, IL‐5, IL‐10 and IL‐21. Principal Component analysis computed on FFA abundances revealed significant differences in the profile of SCFA (p = 0,012), MCFA (p = 0.00015) and LCFA (p = 0,035) between PV patients and HC, which were not significantly changed by immunosuppressive treatments. PV patients showed a significantly lower serum concentration of propionic (p < 0.0005) and butyric (p < 0.0005) acids, SCFA with anti‐inflammatory functions, while hexanoic (p < 0.0005) and hexadecanoic (p = 0.0006) acids, pro‐inflammatory MCFA and LCFA respectively, were over‐represented. Treatments induced a significant decrease of hexanoic (p = 0.035) and a further increase of hexadecanoic (p = 0.046) acids. Positive correlations emerged between IFN‐γ and acetic acid (Rho = 0.60), IFN‐γ and hexanoic acid (Rho = 0.46), IL‐5 and both hexadecanoic acid (Rho = 0.50) and octadecanoic acid (Rho = 0.53), butyric acid and PDAI (Rho = 0.53). PV was associated with a remarked imbalance of circulating FFA compared to HC. The serum alterations of SCFA, MCFA, and LCFA may contribute to promoting inflammation in PV. Deeper insights into the immunomodulatory functions of these molecules may pave the way for personalized dietary interventions in PV patients. [ABSTRACT FROM AUTHOR]

The research aimed to efficiently prepare zinc caprylate using caprylic acid and zinc sulfate as raw materials and explore its antibacterial effects and mechanisms. The experiment employed a saponification and complex decomposition method to chelate caprylic acid with zinc sulfate to generate zinc caprylate, followed by structural characterization. Staphylococcus aureus and Escherichia coli were chosen as models, and the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by a two-fold dilution method to investigate the antibacterial activity of zinc caprylate. The study also examined the impact of zinc caprylate on the cell membrane permeability, biofilm formation, DNA, and protein synthesis of Staphylococcus aureus and Escherichia coli to elucidate its antibacterial mechanism. The results showed that zinc caprylate had a well-defined crystal structure with uniform particle size. It exhibited strong antibacterial effects against both Staphylococcus aureus and Escherichia coli, with the MIC values of 250 and 350 mg/L, respectively, and a stronger inhibitory effect on Staphylococcus aureus. Zinc caprylate disrupted the cell membrane permeability of Staphylococcus aureus and Escherichia coli in a time-dependent manner, inhibited the formation of bacterial biofilms, thus exerting antibacterial effects. However, the impact on DNA and protein synthesis in both Escherichia coli and Staphylococcus aureus was not significant. The study suggests that zinc caprylate demonstrates strong antibacterial activity against both Gram-positive and Gram-negative bacteria by inhibiting biofilm formation and disrupting cell membrane permeability. It holds potential as a substitute for antibiotics in livestock and poultry production. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effects of low-protein (LP) diets supplemented with sodium butyrate (SB), medium-chain fatty acids (MCT), or n-3 polyunsaturated fatty acids (n-3 PUFA) on the growth performance, immune function, and the microbiome of weaned piglets. A total of 120 healthy weaned piglets ((Landrace × Large White × Duroc); 7.93 ± 0.7 kg initial body weight), were randomly divided into five groups. Each group consisted of six replications with four piglets per replication. Dietary treatments included control diet (CON); LP diet (LP); LP + 0.2% SB diet (LP + SB); LP + 0.2% MCT diet (LP + MCT); and LP + PUFA diet (LP + PUFA). The experimental period lasted for 4 weeks. Compared with the CON diet, LP, LP + SB, LP + MCT, and LP + PUFA diets decreased the final weight and average daily gain (ADG) of piglets (p < 0.05). There were lower (p < 0.05) concentrations of IL-8 and higher (p < 0.05) Glutathione peroxidase (GSH-Px) activity in the plasma of piglets fed with LP + SB, LP + MCT, and LP + PUFA diets than those fed with the LP diet. The piglets in the LP + SB and LP + PUFA groups had lower IKK-alpha (IKKa) mRNA expression in the colonic mucosa compared with those in the CON and LP groups (p < 0.05). The mRNA expression of TLR4 in the colonic mucosa of piglets in the LP + SB, LP + MCT, and LP + PUFA groups was decreased when compared with the CON and LP groups (p < 0.05). The LP + MCT diets increased the gene expression of nuclear factor erythroid 2-related factor 2 (Nrf2) in the colonic mucosa of piglets compared with CON, LP, and LP + SB diets (p < 0.05). The abundance of Erysipelotrichaceae in the colonic microbiome of piglets in the LP group was higher than that in the other four groups (p < 0.05). Collectively, this study showed that LP diets supplemented with SB, MCT, or n-3 PUFA reduced plasma inflammatory factor levels, increased plasma GSH-Px activity, and declined mRNA expression of TLR4 and IKKa in the colonic epithelium, whereas it reduced the abundance of Erysipelotrichaceae in the colon of piglets. [ABSTRACT FROM AUTHOR]

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This study aimed to investigate the effects of low-protein (LP) diets supplemented with sodium butyrate (SB), medium-chain fatty acids (MCT), or n-3 polyunsaturated fatty acids (n-3 PUFA) on the growth performance, immune function, and the microbiome of weaned piglets. A total of 120 healthy weaned piglets ((Landrace × Large White × Duroc); 7.93 ± 0.7 kg initial body weight), were randomly divided into five groups. Each group consisted of six replications with four piglets per replication. Dietary treatments included control diet (CON); LP diet (LP); LP + 0.2% SB diet (LP + SB); LP + 0.2% MCT diet (LP + MCT); and LP + PUFA diet (LP + PUFA). The experimental period lasted for 4 weeks. Compared with the CON diet, LP, LP + SB, LP + MCT, and LP + PUFA diets decreased the final weight and average daily gain (ADG) of piglets (p < 0.05). There were lower (p < 0.05) concentrations of IL-8 and higher (p < 0.05) Glutathione peroxidase (GSH-Px) activity in the plasma of piglets fed with LP + SB, LP + MCT, and LP + PUFA diets than those fed with the LP diet. The piglets in the LP + SB and LP + PUFA groups had lower IKK-alpha (IKKa) mRNA expression in the colonic mucosa compared with those in the CON and LP groups (p < 0.05). The mRNA expression of TLR4 in the colonic mucosa of piglets in the LP + SB, LP + MCT, and LP + PUFA groups was decreased when compared with the CON and LP groups (p < 0.05). The LP + MCT diets increased the gene expression of nuclear factor erythroid 2-related factor 2 (Nrf2) in the colonic mucosa of piglets compared with CON, LP, and LP + SB diets (p < 0.05). The abundance of Erysipelotrichaceae in the colonic microbiome of piglets in the LP group was higher than that in the other four groups (p < 0.05). Collectively, this study showed that LP diets supplemented with SB, MCT, or n-3 PUFA reduced plasma inflammatory factor levels, increased plasma GSH-Px activity, and declined mRNA expression of TLR4 and IKKa in the colonic epithelium, whereas it reduced the abundance of Erysipelotrichaceae in the colon of piglets.

Microbial chain elongation has emerged as a valuable bioprocess for obtaining marketable products, such as medium chain fatty acids usable in several industrial applications, from organic waste. The understanding of the microbiology and microbial ecology in these systems is crucial to apply these microbiomes in reliable production processes controlling microbial pathways to promote favourable metabolic processes, which will in turn increase product specificity and yields. In this research, the dynamics, cooperation/competition and potentialities of bacterial communities involved in the long-term lactate-based chain elongation process from food waste extract were evaluated under different operating conditions by DNA/RNA amplicon sequencing and functional profile prediction. The feeding strategies and the applied organic loading rates strongly affected the microbial community composition. The use of food waste extract promoted the selection of primary fermenters (i.e., Olsenella, Lactobacillus) responsible for the in situ production of electron donors (i.e., lactate). The discontinuous feeding and the organic loading rate 15 gCOD L-1 d-1 selected the best performing microbiome in which microbes coexist and cooperate to complete the chain elongation process. Both at DNA and RNA level, this microbiome was composed by the lactate producer Olsenella, the short chain fatty acids producers Anaerostipes, Clostridium sensu stricto 7, C. sensu stricto 12, Corynebacterium, Erysipelotrichaceae UCG-004, F0332, Leuconostoc, and the chain elongator Caproiciproducens. This microbiome also showed the highest predicted abundance of short-chain acyl-CoA dehydrogenase, the functional enzyme responsible for the chain elongation process. The combined approach herein used allowed to study the microbial ecology of chain elongation process from food waste by identifying the main functional groups, establishing the presence of potential biotic interactions within the microbiomes, and predicting metabolic potentialities. This study provided pivotal indications for the selection of high-performance microbiome involved in caproate production from food waste that can serve as a basis for further improving system performance and engineering the process scale-up.

The transition period is the stage of the high incidence of metabolic and infectious diseases in dairy cows. Improving transition dairy cows' health is crucial for the industry. This study aimed to determine the effects of dietary supplementation medium-chain fatty acids (MCFAs) on immune function, metabolic status, performance of transition dairy cows. Twenty multiparous Holstein cows randomly assigned to two treatments at 35 d before calving. 1) CON (fed the basal 2) MCFA treatment (basal diet was supplemented at an additional 20 g MCFAs mixture every day) until 70 d after calving. The results showed that the serum amyloid A myeloperoxidase concentrations in the blood of cows in MCFA treatment significantly decreased during the early lactation (from 1 d to 28 d after calving) 0.03, 0.04, respectively) compared with the CON, while the tumor necrosis factor concentration was significantly decreased at 56 d after calving (P = 0.02). In addition, the concentration of insulin in the pre-calving (from 21 d before calving to calving) blood of cows in MCFA treatment was significantly decreased (P = 0.04), and concentration of triglyceride also showed a downward trend at 28 d after calving 0.07). Meanwhile, MCFAs supplementation significantly decreased the concentrations of lithocholic acid, hyodeoxycholic acid, and hyocholic acid in the blood at 1 d calving (P = 0.02, < 0.01, < 0.01, respectively), and the level of hyocholic acid taurocholic acid concentrations (P < 0.01, = 0.01, respectively) decreased dramatically at 14 d after calving. However, compared with the CON, the pre-calving dry matter intake and the early lactation milk yield in MCFA treatment were significantly decreased (P = 0.05, 0.02, respectively). In conclusion, MCFAs supplementation transition diet could improve the immune function and metabolic status of dairy cows, and the health of transition cows might be beneficial from the endocrine status. [ABSTRACT FROM AUTHOR]

Medium chain fatty acid (MCFA) treatment (0.75% C6, hexanoic; C8, octanoic; C10, decanoic; or equal proportion mixtures of C6:C8:C10:C12 or C8:C10/g; C12 = dodecanoic acid) of aerobically-exposed corn silage on spoilage and pathogenic microbes and rumen fermentation were evaluated in vitro. After 24 h aerobic incubation (37 °C), microbial enumeration revealed 3 log10 colony-forming units (CFU)/g fewer (P = 0.03) wild-type yeast and molds in C8:C10-treated silage than controls. Compared with controls, wild-type enterococci decreased (P < 0.01) in all treatments except the C6:C8:C10:C12 mixture; lactic acid bacteria were decreased (P < 0.01) in all treatments except C6 and the C6:C8:C10:C12 mixture. Total aerobes and inoculated Staphylococcus aureus or Listeria monocytogenes were unaffected by treatment (P > 0.05). Anaerobic incubation (24 h at 39 °C) of ruminal fluid (10 mL) with 0.02 g overnight air-exposed MCFA-treated corn silage revealed higher hydrogen accumulations (P = 0.03) with the C8:C10 mixture than controls. Methane, acetate, propionate, butyrate, or estimates of fermented hexose were unaffected. Acetate:propionate ratios were higher (P < 0.01) and fermentation efficiencies were marginally lower (P < 0.01) with C8- or C8:C10-treated silage than controls. Further research is warranted to optimize treatments to target unwanted microbes without adversely affecting beneficial microbes. [ABSTRACT FROM AUTHOR]

Recently, two oral-administered peptide pharmaceuticals, semaglutide and octreotide, have been developed and are considered as a breakthrough in peptide and protein drug delivery system development. In 2019, the Food and Drug Administration (FDA) approved an oral dosage form of semaglutide developed by Novo Nordisk (Rybelsus®) for the treatment of type 2 diabetes. Subsequently, the octreotide capsule (Mycapssa®), developed through Chiasma's Transient Permeation Enhancer (TPE) technology, also received FDA approval in 2020 for the treatment of acromegaly. These two oral peptide products have been a significant success; however, a major obstacle to their oral delivery remains the poor permeability of peptides through the intestinal epithelium. Therefore, gastrointestinal permeation enhancers are of great relevance for the development of subsequent oral peptide products. Sodium salcaprozate (SNAC) and sodium caprylate (C8) have been used as gastrointestinal permeation enhancers for semaglutide and octreotide, respectively. Herein, we briefly review two approved products, Rybelsus® and Mycapssa®, and discuss the permeation properties of SNAC and medium chain fatty acids, sodium caprate (C10) and C8, focusing on Eligen technology using SNAC, TPE technology using C8, and gastrointestinal permeation enhancement technology (GIPET) using C10. [ABSTRACT FROM AUTHOR]

Maternal food environment can program fecal microbiota in offspring mediated by the imprint of intrauterine conditions. Gut bacteria play a role in host fatty acid and amino acid metabolism. This study aimed to determine the effects of maternal diet on fecal microbiota, and the impact on fatty acid and amino acid metabolism in male offspring rats. Ten male pups from dams fed standard diet (C-C, n = 5) and cafeteria diet (Caf-C, n = 5) were fed standard chow diet for twenty-three weeks. Fresh fecal samples were collected at three and twenty-six weeks of age for fecal microbiota analysis by metagenomic sequencing of the V3-V4 region of the 16S rRNA gene. At the end of the study, serum samples were collected to analyse fatty acids from phospholipid and cholesterol ester fractions by gas chromatography and free amino acids by liquid chromatography. The bacterial abundance from the Actinobacteria and Proteobacteria phyla significantly decreased over time for both groups. Additionally, significant differences were found between C-C and Caf-C groups in these bacterial phyla. In the Caf-C group, Firmicutes and Elusimicrobia phyla increased, while Bacteroidetes decreases in adulthood samples. At the genus level, the abundance of Bacteroides decreased, while Elusimicrobium , Lactobacillus , Turicibacter , Blautia , and Veillonella increased in the Caf-C group. Several metabolites including PL-MCFAs (caprylic acid and capric acid), CE-MUFAs (palmitoleic acid and heptadecenoic acid), and free amino acids aspartate, glutamic acid, and cysteine were significantly higher in Caf-C group. This study underscores the putative programming of offspring fecal microbiota by maternal diet impact. These changes led to alterations fatty acids and amino acids metabolism in adult male offspring rats. [ABSTRACT FROM AUTHOR]

In feed, propionic acid is the weak organic acid of choice to prevent growth of spoilage fungi. For safe and easy industrial handling this antifungal agent is applied in the presence of neutralizing ammonium, which however has the disadvantage to negatively affect the efficacy of fungus-inhibiting properties of the formulation. In the present study we investigated the impact of medium chain fatty acids (MCFA) on the antifungal efficacy of an ammonium propionate formulation on dormant- and germinating conidia as well as germ tubes and hyphae of Aspergillus chevalieri , a xerophilic fungus predominant on moulded feed. Dormant conidia were not affected by 32 mM of ammonium propionate after a 28 h-treatment in demi water. Similar results were obtained with solely 0.52 mM MCFA. However, the combination of both components nearly eradicated formation of colonies from these conidia and was accompanied by distortion of the cellular structure as was visible with light- and transmission electron microscopy. Germination of conidia, characterised by swelling and germ tube formation, was significantly decreased in the presence of 16 mM ammonium propionate and 0.26 mM MCFA, while the latter component itself did not significantly decrease germination. We conclude that a combination of ammonium propionate and MCFA had a synergistic antifungal effect on dormant and germinating conidia. When the combination of ammonium propionate and MCFA was tested on hyphae for 30 min, we observed that cell death was significantly increased in comparison to components alone. Treatment of the hyphae with 16 mM of ammonium propionate caused aberrant mitochondria, as evidenced by irregularly shaped and enlarged mitochondria that contained electron-dense inclusions as observed by transmission electron microscopy. When the combination of ammonium propionate and MCFA was applied against the hyphae, more severe cell damage was observed, with signs of autophagy. Summarised, our results demonstrate synergistic antifungal effects of ammonium propionate and medium chain fatty acids on fungal survival structures, during their germination and after a short (sudden) treatment of growing cells. This is of potential importance for several areas of feed and food storage and shelf-life. • Ammonium propionate and medium chain fatty acids (MCFA) are tested on the feed-spoiling fungus Aspergillus chevalieri. • The combination of the components inhibits different developmental stages of the fungus synergistically. • Dormant conidia of the fungus are inactivated by this combination. • Changes in subcellular structure after treatment are observed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Advancements in MCFAs production through chain elongation were reviewed. • Butyrate accumulation, competition, toxicity determined as rate-limiting steps. • Innovative solutions, key challenges and perspectives were discussed. • Techno-economic analysis of microbial MCFAs production was carried out. The depletion of fossil fuels has prompted an urgent search for alternative chemicals from renewable sources. Current technology in medium chain fatty acids (MCFAs) production though chain elongation (CE) is becoming increasingly sustainable, hence the motivation for this review, which provides the detailed description, insights and analysis of the metabolic pathways, substrates type, inoculum and fermentation process. The main rate-limiting steps of microbial MCFAs production were comprehensively revealed and the corresponding innovative solutions were also critically evaluated. Innovative strategies such as substrate pretreatment, electrochemical regulation, product separation, fermentation parameter optimization, and electroactive additives have shown significant advantages in overcoming the rate-limiting steps. Furthermore, novel regulatory strategies such as quorum sensing and electronic bifurcation are expected to further increase the MCFAs yield. Finally, the techno-economic analysis was carried out, and the future research focuses were also put forward. [ABSTRACT FROM AUTHOR]

[Display omitted] • The VFAs and MCFAs of banana (peel and pulp), cocoa, and coffee have been performed. • The fermentations were performed upon uncontrolled, 6.6 and 5.2 pH conditions. • Acidification rates and acid percentages within 21-day fermentation were reported. • The findings gave interesting results regarding g CARBOX kg−1 TVS for VFAs and MCFAs. • Microbial community taxa were identified to order and genus level for each substrate. Carboxylates generation from banana (peel and pulp), coffee, and cacao fermentation agro-waste, upon uncontrolled and controlled pHs of 6.6 (heat-driven methanogens inactivation) and 5.2 (pH inactivation), was studied. Regarding volatile fatty acids (VFAs), acetic was the highest for cocoa (96.2 g kg−1 TVS) at pH 4.5. However, butyric was relevant for banana pulp (90.7 g kg−1 TVS), at controlled pH 6.6. The highest medium chain fatty acid (MCFAs) level was hexanoic (cocoa, 3.5 g kg−1 TVS), while octanoic reached a maximum of 2.8 g kg−1 TVS for coffee at pH 6.6. At pH 5.2 MCFAs yield was relatively low. Uncontrolled pH conditions, using banana resulted in superior VFAs production compared to controlled conditions. Thus, pH became a determining variable when deciding the time and kind of carboxylic acid to be recovered. The bacterial community at the end of the chain elongation process was dominated by phyla Firmicutes , and Clostridium as the most common genera. [ABSTRACT FROM AUTHOR]

Medium-chain fatty acids (MCFAs) are important components for food, pharmaceutical and fuel industries. Nevertheless, engineering microorganisms to produce MCFAs often induces toxicity and stresses towards host strains, which could be alleviated via accelerating the export of MCFAs from cells. However, current secretory systems are inefficient and require inducible promoters. Here, a multi-layer genome mining and phylogenomic analysis was developed to identify efficient efflux transporters. Firstly, based on the genomic mining of 397 strains throughout various representative species, the evolutionary history of efflux transporters was recapitulated, and further experimental analysis revealed that acrE from Citrobacter exhibited the best performance. Secondly, according to the further mining of 797 Citrobacter genomes and 1084 Escherichia genomes, a detailed phylogenomic analysis of efflux transporter-centric genomic vicinities was performed. This led to the identification of efficient efflux pump combination acrE and acrF. These efflux pumps were then combined with the quorum-sensing circuit from Enterococcus faecalis to regulate MCFA efflux in an autonomous manner, which achieved a 4.9-fold boost in MCFA production and firstly demonstrated the efficient and autonomous efflux pump specially for MCFAs. The integrative omics technologies described here are enabling the utilization of the increasingly large database and the effective mining of target gene diversities.

Static infusion of oak chips in wine is a common practice during wine ageing, aimed at improving sensory properties and stability of wines. The wine/chips contact required to reach the desired effect can last several weeks or months. A low-pressure continuous dynamic (LPCD) extractor in which a closed-circle, low-pressure continuous flow of wine passes through an extraction cell filled with chips, was evaluated as a tool to tune red wine properties in few hours. The aim of this work was to evaluate the effect of the use of a LPCD extractor the effect on color, volatile compounds and sensory properties of a Primitivo wine, as well as to assess the combined effect of LPCD extractor, passive microxygenation through polyethylenetereftalate (PET) containers and exogenous tannins. Their combined effect caused a significant increase of stabilized pigments was observed, without compromising the aroma profile. LPCD extraction, passive micro-oxygenation through plastic materials and enological tannins can be considered as a low-cost, and potentially low-impact, integrated technological platform suitable to tune wine sensory properties and stability, when either traditional approaches (such as barrel aging) or other assisted extraction technologies are not applicable or preferred, even in small wineries., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Polyhydroxyalkanoates (PHAs) production by Aeromonas sp. AC_01 was investigated using synthetic and waste derived short and medium chain fatty acids (SMCFAs). The obtained results revealed that the analyzed bacterial strain was able to grow and synthesize PHAs using SMCFAs. The highest PHA productivity was observed in the cultivation supplemented with a mixture of acetic acid and butyric acid (3.89 mg/L·h). Furthermore, SMCFAs-rich stream, derived from acidogenic mixed culture fermentation of acid whey, was found to be less beneficial for PHA productivity than its synthetic mixture, however the PHA production was favored by the nitrogen-limited condition. Importantly, Aeromonas sp. AC_01 was capable of synthesizing novel scl-mcl copolymers of 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV), 3-hydroxytridecanoate (3HtriD) and/or 3-hydroxytetradecaonate (3HTD) with high 3HB and 3HV fractions. They were identified with alterable monomers composition depending on the culture conditions used. Moreover, in-depth thermal analyses proved that they are highly resistant to thermal degradation regardless of their monomeric composition. The obtained results confirm that Aeromonas sp. AC_01 is a promising candidate for the biotechnological production of PHAs from SMCFAs with thermal properties that can be tuned together with their chemical composition by the corresponding adjustment of the cultivation process. [ABSTRACT FROM AUTHOR]

Medium chain fatty acids (MCFA) are saturated fatty acids containing 6~12 carbon atoms, which have special physiological functions such as easy absorption, growth promotion, broad-spectrum antibacterial and maintenance of intestinal health. Dietary MCFAs can be added alone or combined with organic acids and probiotics, which can improve the growth performance of animals and enhance body immunity. The effect of MCFAs is similar to that of antibiotics and zinc oxide. The paper reviews the physicochemical, metabolic and functional properties of MCFAs and its application in pig production,to provide reference for the application of MCFAs in pig industry. [ABSTRACT FROM AUTHOR]

Lipases are extensively used for regiospecific esterification of polyols with fatty acids. However, side reactions generating byproducts limited the enzymes for industrial applications. Here, we have engineered the substrate-binding site of Candida antarctica lipase B (CALB) to improve selectivity for monoacylation of glycerol using medium chain fatty acids (e.g., nonanoic acid) as acyl donors. The enzyme engineering was based on the substrate-binding region of a lipase from Penicillium camemberti (i.e., Lipase G), which showed very high selectivity for monoacylation of glycerol with medium chain fatty acids (e.g., decanoic acid) but low reaction rates. One of the CALB variants (e.g., CALBA282E/I285F), which was designed to have a narrow substrate binding region, has exhibited ca. 2-fold greater selectivity for the synthesis of 1-monoacyl-sn-glycerol with n-nonanoic acid. The double mutant allowed the production of 1-nonanoyl-glycerol to a concentration of 2.27 M in glycerol to a reaction rate of 1.0 M/h. This study will contribute to the use of lipases for regiospecific esterification of polyols with carboxylic acids. [ABSTRACT FROM AUTHOR]

SUMMARY: Mitigation of food pathogens, such as Salmonella, continues to be a focus in poultry production, whether on shell eggs or meat products. No single mitigation approach is fully capable of eliminating the risk of Salmonella contamination, but rather multicomponent, comprehensive strategies are now used to mitigate the risk. Targeted in-feed additives are a component of a food safety program and may help to reduce Salmonella infection. This study evaluated the efficacy of a medium chain fatty acid (MCFA) feed-additive product to reduce Salmonella Enteritidis (S. E.) infection in commercial layer hens. One-hundred and forty-four 1-day-old Hy-line pullets were raised on new litter until 10 wk of age when they were moved into individual cages. There were 3 treatments, 1) Control, 2) MCFA given d 0-termination, and 3) MCFA given wk 10-termination. MCFA blend was a mixture of C6, C8, and C10 acids. At 17 wk-of-age each bird was orally challenged with 3 × 106 CFU/bird of a nalidixic acid resistant S.E. strain. Seven- and 14-d postchallenge, ceca and ovaries were aseptically collected and cultured for S.E. Significant differences (P < 0.05) in mean cecal S.E. log10 MPN/g were observed between 7 d postinfection compared with 14 d postinfection. Fourteen days post infection, MCFA d 0 birds had significantly (P < 0.05) lower prevalence than the untreated group and the MCFA (wk 10) group did not differ significantly from either of the other 2 groups. No significant differences (P < 0.05) in prevalence and mean ovary S.E. log10 MPN/g were observed. Inclusion of MCFA d 0-termination resulted in reduction of S.E. infection in ceca's, but this benefit was not seen in ovary S.E. prevalence.

ABSTRACT In our experiment, coconut and palm oil supplementation was added to the diet of broiler chickens to prove the hypothesis that medium chain fatty acids (MCFAs) can reduce the occurrence of potential pathogens (Clostridium perfingens, Coliform) in gut microflore and therefore improve bird welfare. Cobb 500 cockerels were divided in five groups. Control birds were fed commercial broiler diet, while birds in the four treatment group diets were supplemented with coconut, palm oil, or a combination of the two, respectively. As a positive control, sunflower oil supplementation was included in the diet of the fifth group. During the 28 days of the study (from 14 to 42 days of life), 5 samplings were scheduled, when excreta samples were taken from the litter to analyse total microbial count and the number of Clostridia, Coliforms, and Salmonella. According to the results of microbiological analysis, coconut oil supplementation led to the continuous decline of Clostridium perfringens numbers until they vanished by the end of the experimental period. A similar but faster decline was found as a result of palm oil and the combined (palm oil+coconut oil) treatment. However, the number of Coliforms and total microbial count changed only slightly by the end of the study. No Salmonella spp. was present in the samples throughout the experiment. Altogether, coconut and palm oil supplementation has a beneficial effect on the microbiological composition of poultry litter.

Outbreaks of African swine fever virus (ASFv) and porcine epidemic diarrhoea virus (PEDv) have revealed the susceptibility of livestock to disease transmitted through feed. Several viruses, including PEDv, survive in feed and may introduce disease that causes significant morbidity and mortality. In 2013, PEDv, which causes severe diarrhoea and vomiting, reached North America after spreading for decades across Eurasia. The global exchange of ingredients has created demand for products that prevent disease transmission from feed. Formaldehyde‐based products are highly effective at inactivating enveloped viruses when applied at 3.25 kg/t. Alternative products to formaldehyde, including carboxylic acids, essential oils and medium chain fatty acids (MCFAs), have exhibited mixed efficacy against PEDv and require application rates higher than formaldehyde. Amphiphilic molecules like MCFAs disrupt the bilayer‐lipid membranes that protect viral nucleic acids through the formation of micelles. Monoglycerides form micelles at lower concentrations than MCFAs, which suggests they may be more potent against enveloped viruses. The potential efficacy of monoglycerides against enveloped viruses in feed led to the development and examination of an experimental monoglyceride blend. The proprietary monoglyceride blend significantly (p <.0001) reduced PEDv viability in vitro after application to feed at 1.5, 2.5 and 3.5 kg/t. The monoglyceride was tested in a natural feeding behaviour challenge model in piglets. The feed was contaminated with ice‐blocks containing viable PEDv, and the piglets were exposed to PEDv through the feed bin for 20 days. At the end of the 20‐day challenge period, all pigs were rectally swabbed and tested for PEDv by qPCR. In the untreated control group 54.8% of the piglets tested positive for PEDv, whereas none of the MCFA‐treated feed (10 kg/t inclusion) transmitted PEDv. Strikingly, the monoglyceride‐treated groups (1.5, 2.5 and 3.5 kg/t) all exhibited 100% protection from PEDv. These data support the use of this proprietary monoglyceride blend in mitigation and prevention of viral disease transmission to piglets from contaminated feed. [ABSTRACT FROM AUTHOR]

Copyright of Zywnosc is the property of Polish Society of Food Technologists - Scientific Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Background We hypothesized that supplementation of nursery and grower pig diets with coconut oil in the absence of antibiotics would yield maintenance of glucose homeostasis, growth performance, and immune function similar to what is achieved with nursery and grower pig diets containing antibiotics. Pigs received the same base treatment diets from d24 (weaning) to d71 of age and had blood and fecal samples collected on d24, d31, d45 and d71 for measurement of whole blood glucose, serum insulin, cortisol and cytokines, and fecal microbiome. Pigs had weekly weights and daily feed consumption measured throughout the study. Animals were euthanized at d71 and subcutaneous fat and ileal contents were collected for assessment for fatty acids and microbiome, respectively. Diet treatments consisted of 2% soybean oil plus antibiotics (ABX; n = 22), 2% soybean oil without antibiotics (NABX; n = 22), and 2% coconut oil without antibiotics (COC; n = 22). Statistical analysis examined the effect of diet within each timepoint using a repeated measures ANOVA. Results Pigs fed COC diet had decreased serum insulin levels, maintained feed intake, feed conversion and weight gain, and, based on serum cytokines and fecal microbiome, were immunologically similar to ABX-fed pigs. However, NABX-fed pigs performed similarly to the ABX-fed pigs in all parameters except for serum cytokines. Additionally, there was no difference in the incidence of diarrhea between any of the diet treatments. Conclusions This study demonstrates that dietary antibiotics are not necessary to maintain growth performance in nursery and grower pigs. However, dietary antibiotics appear to modulate circulating cytokine levels. Dietary coconut oil is neither harmful nor helpful to growth performance or immune function in nursery and grower pigs but does modulate serum insulin levels. Therefore, while coconut oil fed at 2% by weight is a suitable substitute for dietary antibiotics, this study suggests that no substitute for dietary antibiotics is needed at all.

Alternative therapies for cancer treatment have been developed using bioactive compounds such as betulinic acid (BA). The objective of this study was to investigate the bioactivity of BA in its free form and compare it with its nano-encapsulated form under a skin carcinogenesis protocol in a genetically modified murine model. K14E6 and FVB mice were divided into four groups to be treated with free BA and with betulinic acid nanoemulsion (BANE). Lecithin enriched with medium chain fatty acids (MCFAs) was employed as an emulsifier to prepare the nanoemulsions with a mean droplet size of 40 nm. Skin tumors were induced by exposure to DMBA and TPA directly to the transgenic mice. Tumor development was completely inhibited by BANE and by 70% with free BA. This was validated by histological sections and the gene expression of the Cdk4 and Casp8 genes.

Recently, two oral-administered peptide pharmaceuticals, semaglutide and octreotide, have been developed and are considered as a breakthrough in peptide and protein drug delivery system development. In 2019, the Food and Drug Administration (FDA) approved an oral dosage form of semaglutide developed by Novo Nordisk (Rybelsus®) for the treatment of type 2 diabetes. Subsequently, the octreotide capsule (Mycapssa®), developed through Chiasma’s Transient Permeation Enhancer (TPE) technology, also received FDA approval in 2020 for the treatment of acromegaly. These two oral peptide products have been a significant success; however, a major obstacle to their oral delivery remains the poor permeability of peptides through the intestinal epithelium. Therefore, gastrointestinal permeation enhancers are of great relevance for the development of subsequent oral peptide products. Sodium salcaprozate (SNAC) and sodium caprylate (C8) have been used as gastrointestinal permeation enhancers for semaglutide and octreotide, respectively. Herein, we briefly review two approved products, Rybelsus® and Mycapssa®, and discuss the permeation properties of SNAC and medium chain fatty acids, sodium caprate (C10) and C8, focusing on Eligen technology using SNAC, TPE technology using C8, and gastrointestinal permeation enhancement technology (GIPET) using C10.

Alternative therapies for cancer treatment have been developed using bioactive compounds such as betulinic acid (BA). The objective of this study was to investigate the bioactivity of BA in its free form and compare it with its nano-encapsulated form under a skin carcinogenesis protocol in a genetically modified murine model. K14E6 and FVB mice were divided into four groups to be treated with free BA and with betulinic acid nanoemulsion (BANE). Lecithin enriched with medium chain fatty acids (MCFAs) was employed as an emulsifier to prepare the nanoemulsions with a mean droplet size of 40 nm. Skin tumors were induced by exposure to DMBA and TPA directly to the transgenic mice. Tumor development was completely inhibited by BANE and by 70% with free BA. This was validated by histological sections and the gene expression of the Cdk4 and Casp8 genes. [ABSTRACT FROM AUTHOR]

Copyright of Acta Agriculturae Zhejiangensis is the property of Acta Agriculturae Zhejiangensis Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Chain elongation fermentation allows for the synthesis of biobased chemicals from complex organic residue streams. To expand the product spectrum of chain elongation technology and its application range we investigated 1) how to increase selectivity towards branched chain elongation and 2) whether alternative branched carboxylates such as branched valerates can be used as electron acceptors. Elongation of isobutyrate elongation towards 4-methyl-pentanoate was achieved with a selectivity of 27% (of total products, based on carbon atoms) in a continuous system that operated under CO2 and acetate limited conditions. Increasing the CO2 load led to more in situ acetate formation that increased overall chain elongation rate but decreased the selectivity of branched chain elongation. A part of this acetate formation was related to direct ethanol oxidation that seemed to be thermodynamically coupled to hydrogenotrophic carboxylate reduction to corresponding alcohols. Several alcohols including isobutanol and n-hexanol were formed. The microbiome from the continuous reactor was also able to form small amounts of 5-methyl-hexanoate likely from 3-methyl-butanoate and ethanol as substrate in batch experiments. The highest achieved concentration of isoheptanoate was 6.4 ± 0.9 mM Carbon, or 118 ± 17 mg/L, which contributed for 7% to the total amount of products (based on carbon atoms). The formation of isoheptanoate was dependent on the isoform of branched valerate. With 3-methyl-butanoate as substrate 5-methylhexanoate was formed, whereas a racemic mixture of L/D 2-methyl-butanoate did not lead to an elongated product. When isobutyrate and isovalerate were added simultaneously as substrates there was a large preference for elongation of isobutyrate over isovalerate. Overall, this work showed that chain elongation microbiomes can be further adapted with supplement of branched-electron acceptors towards the formation of iso-caproate and iso-heptanoate as well as that longer chain alcohol formation can be stimulated.

The chain elongation bioprocess for the production of medium-chain carboxylates (MCCs) is promising for resource recovery from organic wastes. In this study, the microbiome development and metabolic interactions in chain elongation system with 10% granular activated carbon (GAC, size between 1.5–2 mm) were investigated. The bioreactor achieved an electron recovery rate over 70%, and the carbon distribution towards caproate was over 64%. Additionally, the microbial community structure shifted and chain elongation microbiome rapidly acclimated from traditional anaerobic fermentation consortia. The taxonomic composition shifted in favor of MCCs production by enriching the key microbes associated with caproate production. Caproate-producing Clostridium (75% abundance) and proteolytic Proteiniphilum remarkably predominated in the microbial community. Further metagenomics analysis recovered genome bins of Clostridium kluyveri , Clostrium indolis , Clostridium aminovalericum and Proteiniclasticum ruminis , which together represented the majority of the microbial community. Among them, the complete ethanol-acetate fermentation for caproate production via the reversed β-oxidation pathway (RBO) and fatty acid biosynthesis (FAB) pathway were fully recovered, suggesting that both the pathways contributed to MCCs formation. Further metabolic pathways analysis suggested that microbial metabolic exchanges between chain elongator and symbiotic bacteria, such as cross-feeding of acetate and acetyl-CoA, is vital to shape a robust microbial ecosystem. • GAC enhanced MCCs formation with an electron recovery rate over 70%. • The carbon distribution towards caproate reached 64%. • Microbial taxonomic composition shifted in favor of the production of MCCs. • Both reversed β-oxidation and fatty acid biosynthesis pathways contributed to MCCs formation. • Cross-feeding between chain elongator and symbiotic bacteria is vital to the ecosystem. [ABSTRACT FROM AUTHOR]

Widely acclaimed as the "tree of life," the coconut is intrinsically woven into human culture as a source of food, shelter, and medicine. Coconut oil and its derivatives have found diverse applications in both food and industry. Of late, the consumption of coconut in the form of oil and its derivatives has been proven to be beneficial. Taking into account the most recent clinical evidences, an attempt was made to present a concise review of the cardioprotective, neuroprotective, and anti-obesity effects of coconut and its derivatives. Our analysis reveals that research evidence supports the cardioprotective and neuroprotective effects of coconut. Numerous clinical trials have proven the anti-obesity and hypoglycemic effects of coconut oil and products. High contents of myocardial anti-oxidants, and differential metabolism of medium chain fatty acids (MCFAs) provide cardioprotective effects. The ketogenic effect of coconut derived products confers neuroprotective measures and enhanced energy expenditure in the metabolism of MCFAs and polyphenolic anti-oxidants are suggested to offer anti-obesity effects. Nevertheless, further research with more randomized, controlled, large clinical trials that evaluate the optimal dosage and side effects, if any, are warranted. Based on this comprehensive review, it is understood that MCFAs are the key component, apart from the phytochemicals such as polyphenols, tocopherols, and other antioxidants that accord these health benefits. Overall, the health benefits of coconut and its derivatives are perceptible, though there is a need for long-term clinical trials. Also a shift of research focus from coconut fatty acids and oil to other phytochemicals and to design appropriate clinical and epidemiological studies to discover coconut biomolecules of health importance is warranted. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ammonia inhibited chain elongation of ethanol as ED. • Hydrochar alleviated the ammonia inhibition on chain elongation. • Ammonia inhibited Acetyl-CoA production and the RBO pathway. • UBA4085 sp.FDU78 as an ammonia-tolerant bacteria enriched at 1–4 g-N/L ammonia. • The uptake of K+, energy and osmoprotectants were key to ammonia tolerance. The production of medium chain fatty acids (MCFAs) through chain elongation (CE) from organic wastes/wastewater has attracted much attention, while the effects of a common inhibitor-ammonia has not been elucidated. The mechanism of ammonia affecting CE was studied by metagenomic. The lag phase duration of caproate production was increased, and the maximum caproate production rate was decreased by 43.4 % at 4 g-N/L, as compared to 0 g-N/L. And hydrochar (HC) alleviated the inhibition of ammonia at 4 g-N/L. Metagenomic analysis indicated that ammonia induced UBA4085 sp.FDU78 as the dominant microorganism, and metabolic reconstruction revealed its potential CE ability. Furthermore, ammonia inhibited the reverse β oxidation pathway and Acetyl-CoA production pathway. The tolerance of UBA4085 sp.FDU78 to ammonia was associated with the uptake of inorganic ions, energy conservation, and synthesis of osmoprotectants. The present study provided a deep-insight on the ammonia tolerance mechanism on the CE process. [ABSTRACT FROM AUTHOR]

• mmBCFA levels in human milk vary with gestational weight gain. • De novo synthesis can account for as much as 50 % of the levels of specific mmBCFAs in murine milk. • High fat diet decreases the amount of de novo synthesized mmBCFAs in murine milk. Breastfeeding is an important determinant of infant health and there is immense interest in understanding its metabolite composition so that key beneficial components can be identified. The aim of this research was to measure the fatty acid composition of human milk in an Irish cohort where we examined changes depending on lactation stage and gestational weight gain trajectory. Utilizing a chromatography approach optimal for isomer separation, we identified 44 individual fatty acid species via GCMS and showed that monomethyl branched-chain fatty acids(mmBCFA's), C15:0 and C16:1 are lower in women with excess gestational weight gain versus low gestational weight gain. To further explore the potential contribution of the activity of endogenous metabolic pathways to levels of these fatty acids in milk, we administered D 2 O to C57BL/6J dams fed a purified lard based high fat diet (HFD) or low-fat diet during gestation and quantified the total and de novo synthesized levels of fatty acids in their milk. We found that de novo synthesis over three days can account for between 10 and 50 % of mmBCFAs in milk from dams on the low-fat diet dependent on the branched-chain fatty acid species. However, HFD fed mice had significantly decreased de novo synthesized fatty acids in milk resulting in lower total mmBCFAs and medium chain fatty acid levels. Overall, our findings highlight the diverse fatty acid composition of human milk and that human milk mmBCFA levels differ between gestational weight gain phenotypes. In addition, our data indicates that de novo synthesis contributes to mmBCFA levels in mice milk and thus may also be a contributory factor to mmBCFA levels in human milk. Given emerging data indicating mmBCFAs may be beneficial components of milk, this study contributes to our knowledge around the phenotypic factors that may impact their levels. [ABSTRACT FROM AUTHOR]

Polyhydroxyalkanoates (PHAs) production by Aeromonas sp. AC_01 was investigated using synthetic and waste derived short and medium chain fatty acids (SMCFAs). The obtained results revealed that the analyzed bacterial strain was able to grow and synthesize PHAs using SMCFAs. The highest PHA productivity was observed in the cultivation supplemented with a mixture of acetic acid and butyric acid (3.89 mg/L·h). Furthermore, SMCFAs-rich stream, derived from acidogenic mixed culture fermentation of acid whey, was found to be less beneficial for PHA productivity than its synthetic mixture, however the PHA production was favored by the nitrogen-limited condition. Importantly, Aeromonas sp. AC_01 was capable of synthesizing novel scl-mcl copolymers of 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV), 3-hydroxytridecanoate (3HtriD) and/or 3-hydroxytetradecaonate (3HTD) with high 3HB and 3HV fractions. They were identified with alterable monomers composition depending on the culture conditions used. Moreover, in-depth thermal analyses proved that they are highly resistant to thermal degradation regardless of their monomeric composition. The obtained results confirm that Aeromonas sp. AC_01 is a promising candidate for the biotechnological production of PHAs from SMCFAs with thermal properties that can be tuned together with their chemical composition by the corresponding adjustment of the cultivation process.

This review outlines the road map for the production of medium chain fatty acids (MCFAs) from organic wastes by adapting the conventionally methanogenic process of anaerobic digestion (AD) for the production of volatile acids and the subsequent chain elongation, as well as for the production of hydrogen. The article analyses the state-of-the-art of these processes and discusses the modifications involved, the bottlenecks, challenges and opportunities. In particular, the various methods of inhibition of methanogenesis are described, their applicability is discussed and investigation of the use of naturally occurring inhibitors like bromoform is suggested. The review concludes that the using AD for MCFA production has a strong potential as a circular economy solution, avoiding many issues with the use of AD for biogas production while creating more economically viable products. The main bottleneck identified here is the downstream separation and extraction of the products. Standardization across studies and implementation of the various methods at pilot scale levels are critical to develop a clearer idea of the viability of the MCFA production process. More in-depth studies on the inhibition process and detailed cost–benefit and life cycle analysis are also recommended to for the use of this process and for its acceptance as a bioeconomy solution. [ABSTRACT FROM AUTHOR]

Thlaspi arvense L. (pennycress) is a cold-tolerant Brassicaceae that produces large amounts of seeds rich in triacylglycerols and protein, making it an attractive target for domestication into an offseason oilseed cash cover crop. Pennycress is easily genetically transformed, enabling synthetic biology approaches to tailor oil properties for specific biofuel and industrial applications. To test the feasibility in pennycress of producing TAGs and acetyl-TAGs rich in medium-chain fatty acids (MCFAs; C6–C14) for industrial, biojet fuel and improved biodiesel applications, we generated transgenic lines with seed-specific expression of unique acyltransferase (LPAT and diacylglycerol acyltransferase) genes and thioesterase (FatB) genes isolated from Cuphea viscosissima, Cuphea avigera var. pulcherrima, Cuphea hookeriana, Coco nucifera, and Umbellularia californica. Wild-type pennycress seed TAGs accumulate no fatty acids shorter than 16C and less than 5 mol percent C16 as palmitic acid (16:0). Co-expressing UcFatB and CnLPAT produced up to 17 mol% accumulation of lauric acid (12:0) in seed TAGs, whereas CvFatB1 CvLPAT2 CpDGAT1 combinatorial expression produced up to 27 mol% medium chain FAs Medium Chain Fatty Acids mostly in the form of capric acid (10:0). CpFatB2 ChFatB2 combinatorial expression predominantly produced, in equal parts, up to 28 mol% myristic acid (14:0) and palmitic acid. Genetically crossing the combinatorial constructs into a fatty acid elongation1 (fae1) mutant that produced no 22:1 erucic acid, and with an Euonymus alatus diacylglycerol acetyltransferase (EaDAcT)-expressing line that produced 60 mol% acetyl-TAGs, had no or relatively minor effects on MCFAs accumulation, suggesting fluxes to MCFAs were largely unaltered. Seed germination assays revealed no or minor delays in seed germination for most lines, the exception being CpFatB2 ChFatB2-expressing lines, which had substantially slower seed germination rates. Taken together, these data show that pennycress can be engineered to produce seeds accumulating modest amounts of MCFAs of varying carbon-chain length in TAGs and acetyl-TAGs, with rates of seed germination being delayed in only some cases. We hypothesize that increasing MCFAs further may require functional reductions to endogenous transferases and/or other FA elongases.

Aromatic wines produced from 'Tămăioasă românească' variety can be fermented to dryness, but they are usually preferred with residual sugar. To preserve some of the sugar unfermented the natural alcoholic fermentation can be stopped by several methods. One of the newest methods researched is the use of medium chain fatty acids, which are naturally produced by yeasts and are also inhibitors of fermentation. In this study doses of 10-30 mg/l of octanoic and decanoic acids, as well as combinations of both acids in doses of 15 mg/l were used to inhibit the fermentation of wines inoculated with 2 different yeast strains. The final sugar content of the resulted wines along with some other physicochemical and sensory parameters were determined and compared. Our preliminary observations showed that the inhibition is dose dependent and also that the decanoic acid tends to be more inhibitory than octanoic acid. [ABSTRACT FROM AUTHOR]

This study considers the use of Jerusalem artichoke (Helianthus tuberosus) tuber powder (HTT) and medium/ long-chain fatty acids (MLCFAs) in the nutrition of laying hens. A total of forty; 30-week-old laying hens were randomly distributed into four groups: control (C), 0.1% MLCFAs (T1), 2.0% HTT (T2), and both 0.1% MLCFAs and 2.0% HTT (T3). The fatty acid (FA) profile of eggs was analysed by gas chromatography, cholesterol by HPLC, and egg quality using a multifunctional automatic egg analyzer; production parameters of hens were also analysed. The results revealed that MLCFAs had a significant effect on accumulation of ô€„-linolenic acid (C18:3) and docosahexaenoic acid (C22:6) in egg yolk, but a higher impact on addition of HTT and MLCFAs was observed. Omega-3 FAs and omega-6/omega-3 FA ratio in egg yolk increased significantly on addition of MLCFAs alone or in combination with HTT. There were no significant effects of HTT and/or MLCFAs on body weight, feed intake, feed conversion ratio or egg mass output of laying hens. In addition, for HTT alone or in combination with MLCFAs, egg shell breaking strength was increased significantly (by 2%). A significant increase of Haugh unit was determined in the MLCFA group and in the HTT group. A significant decrease of cholesterol level was observed in all experimental groups. Supplementing laying hens' feed with HTT and MLCFAs facilitated the production of FAsenriched eggs. Slight effects of HTT and MLCFAs on egg quality, except Haugh unit, yolk cholesterol level and eggshell strength) and production performance of laying hens were observed.

The fastidious nature of Brachyspira hyodysenteriae limits an accurate in vitro pre-screening of conventionally used antibiotics and other candidate alternative antimicrobials. This results in a non-judicious use of antibiotics, leading to an exponential increase of the antibiotic resistance issue and a slowdown in the research for new molecules that might stop this serious phenomenon. In this study we tested four antibiotics (tylosin, lincomycin, doxycycline, and tiamulin) and medium-chain fatty acids (MCFA; hexanoic, octanoic, decanoic, and dodecanoic acid) against an Italian field strain of B. hyodysenteriae and the ATCC 27164 strain as reference. We determined the minimal inhibitory concentrations of these substances, underlining the multidrug resistance pattern of the field strain and, on the contrary, a consistent and stable inhibitory effect of the tested MCFA against both strains. Then, sub-inhibitory concentrations of antibiotics and MCFA were examined in modulating a panel of B. hyodysenteriae virulence genes (tlyA, tlyB, bhlp16, bhlp29.7, and bhmp39f). Results of gene expression analysis were variable, with up- and downregulations not properly correlated with particular substances or target genes. Decanoic and dodecanoic acid with their direct and indirect antimicrobial property were the most effective among MCFA, suggesting them as good candidates for subsequent in vivo trials.

Abstract Background Oleaginous yeast Yarrowia lipolytica is an organism of choice for the development of biofuel and oleochemicals. It has become a chassis for metabolic engineering in order to produce targeted lipids. Understanding the function of key-enzymes involved in lipid metabolism is essential to design better routes for enhanced lipid production and for strains producing lipids of interest. Because medium chain fatty acids (MCFA) are valuable compounds for biokerosene production, we previously generated strains capable of producing MCFA up to 12% of total lipid content (Rigouin et al. in ACS Synth Biol 6:1870–1879, 2017). In order to improve accumulation and content of C14 fatty acid (FA), the elongation, degradation and accumulation of these MCFA in Yarrowia lipolytica were studied. Results We brought evidence of the role of YALI0F0654 (YlELO1) protein in the elongation of exogenous or de novo synthesized C14 FA into C16 FA and C18 FA. YlELO1 deletion into a αFAS_I1220W expressing strain leads to the sole production of C14 FA. However, because this strain does not provide the FA essential for its growth, it requires being cultivated with essential fatty acids and C14 FA yield is limited. To promote MCFA accumulation in Y. lipolytica without compromising the growth, we overexpressed a plant diglyceride acyltransferase specific for MCFA and reached an accumulation of MCFA up to 45% of total lipid content. Conclusion We characterized the role of YlELO1 in Y. lipolytica by proving its involvement in Medium chain fatty acids elongation. We showed that MCFA content can be increased in Yarrowia lipolytica by promoting their accumulation into a stable storage form (triacylglycerides) to limit their elongation and their degradation.

Cell differentiation is an orderly process that begins with modifications in gene expression. This process is regulated by the acetylation state of histones. Removal of the acetyl groups of histones by specific enzymes (histone deacetylases, HDAC) usually downregulates expression of genes that can cause cells to differentiate, and pharmacological inhibitors of these enzymes have been shown to induce differentiation in several colon cancer cell lines. Butyrate at high (mM) concentration is both a precursor for acetyl-CoA and a known HDAC inhibitor that induces cell differentiation in colon cells. The dual role of butyrate raises the question whether its effects on HT29 cell differentiation are due to butyrate metabolism or to its HDAC inhibitor activity. To distinguish between these two possibilities, we used a tracer-based metabolomics approach to compare the metabolic changes induced by two different types of HDAC inhibitors (butyrate and the non-metabolic agent trichostatin A) and those induced by other acetyl-CoA precursors that do not inhibit HDAC (caprylic and capric acids). [1,2-13C2]-d-glucose was used as a tracer and its redistribution among metabolic intermediates was measured to estimate the contribution of glycolysis, the pentose phosphate pathway and the Krebs cycle to the metabolic profile of HT29 cells under the different treatments. The results demonstrate that both HDAC inhibitors (trichostatin A and butyrate) induce a common metabolic profile that is associated with histone deacetylase inhibition and differentiation of HT29 cells whereas the metabolic effects of acetyl-CoA precursors are different from those of butyrate. The experimental findings support the concept of crosstalk between metabolic and cell signalling events, and provide an experimental approach for the rational design of new combined therapies that exploit the potential synergism between metabolic adaptation and cell differentiation processes through modification of HDAC activity.

Alzheimer’s disease (AD), the most common cause of dementia in the elderly population, is closely linked to a dysregulated cerebral lipid homeostasis and particular changes in brain fatty acid (FA) composition. The abnormal extracellular accumulation and deposition of the peptide amyloid-β (Aβ) is considered as an early toxic event in AD pathogenesis, which initiates a series of events leading to neuronal dysfunction and death. These include the induction of neuroinflammation and oxidative stress, the disruption of calcium homeostasis and membrane integrity, an impairment of cerebral energy metabolism, as well as synaptic and mitochondrial dysfunction. Dietary medium chain fatty acids (MCFAs) and polyunsaturated ω-3-fatty acids (ω-3-PUFAs) seem to be valuable for disease modification. Both classes of FAs have neuronal health-promoting and cognition-enhancing properties and might be of benefit for patients suffering from mild cognitive impairment (MCI) and AD. This review summarizes the current knowledge about the molecular mechanisms by which MCFAs and ω-3-PUFAs reduce the cerebral Aβ deposition, improve brain energy metabolism, and lessen oxidative stress levels.